Impulse producing circuit



Jan. 24, 1939., R. L. MILLER IMPULSE PRODUCING CIRCUIT Filed Nov. 18, 1936 m1 VEA/ TOR Q. L. M/LLQ? Patented Jan. 24, 1939 v 2,144,847

UNITED STATES PATENT OFFICE IMPULSE PRODUCING CIRCUIT Ralph L. Miller, Bloomfield, N. J., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application November 18, 1936, Serial No. 111,398

8 Claims. (Cl. 175-373) This invention relates to an impulse producing possible application by way of example, in checkcircuit and particularly to such a circuit including the operation of a time indicating device, ing a condenser which is charged and discharged impulses produced at one point under control of at periodic intervals. the clockwork mechanism being transmitted to An object of the invention is to render readily a central location where the impulses may be 5 distinguishable impulses produced by discharge recorded and compared with standard time sigof the condenser from impulses produced by nals. In such a checking system the significant charging of the condenser. impulses which it is desirable to record are usu- It is more or less common practice to utilize a ally the discharge impulses, that is, the impulses 10 condenser, charged and discharged at periodic occurring when the circuit is abruptly opened 10 intervals, to produce impulses for various purby the clockwork controlled mechanism. Cam poses in electrical circuits. In certain instances I0 is shown in the drawing driven at a regulated of the use of such an arrangement it has been rate by a clock mechanism ll. The cam confound desirable to be able to distinguish the imtrols the position of contact spring 52 which pulses produced by discharge of the condenser cooperates with contact I3 to open and close the 15 from those produced by charging of the conimpulse producing circuit. When the circuit is denser and vice versa. One type of impulse may closed, as shown in the drawing, current from be the significant one for the purpose for which battery ll, flows in the direction indicated by the the circuit is being used and, for this reason, a arrows (full lines), condenser l8 being charged person monitoring on the circuit may wish to to the voltage of the battery due to the voltage 20 pick out such impulses and to disregard the drop across resistance 19. Due to the action of other type of impulses. Also, if the impulses are rectifier 2i which is connected in series with pribeing recorded it may be desirable to record only mary winding 22 of repeat coil 23, the impedance the significant impulses or at least to record the offered to the current passing through the pri- 25 significant impulses in such a manner that they mary winding in the charging direction is rela- 25 will be readily distinguishable from the other tively large so that the amplitude of the imrecorded impulses. pulse now induced in the secondary El, i. e., the

In accordance with a feature of the present charge impulse, is relatively low. While it is invention, the amplitude of the significant type desirable that the value of resistance id be relaof impulses is caused to be materially greater tively high, it must be substantially less than the 31} than the amplitude of the other type of imreverse resistance of rectifier 2i, i. e., the re pulses whereby the significant type of impulses sistance oifered thereby to currents in the chargmay be readily distinguished from the other iming direction. pulses. Now as cam ill is rotated in a clockwise direc- 35 In accordance with a specific embodiment of tion, a short distance from the position illus- 35 the invention a unidirectional current conducttrated, contact spring i2 drops down opening the ing device, such as a copper-oxide rectifier, is so impulse producing circuit at contact l3 whereby associated with the condenser and other elecondenser l8 discharges abruptly through priments of the impulse producing circuit that the mary 22 or" repeat coil 23 in the direction indiimpedance offered to the discharge impulses is cated by the arrow (broken line) thereby induc- 4G much less than that offered to the charge iming an impulse in secondary 2? of the repeat pulses. Since the amplitude of the impulses coil. The impedance oiiered to the discharge decreases as the impedance of the circuit incurrent by rectifier 25 is practically nil so that creases and vice versa. it follows that the amplithe amplitude of the "discharge impulse now tude of the discharge impulses Will be substaninduced in secondary 2? is much greater than 45 tially greater than that of the charge impulses. that of the charge impulse, rectifier 24, as

A thorough understanding of the invention previously pointed out, offering a high impedance and of the various advantageous features thereof to the charge impulse. may be gained from consideration of the follow- Secondary winding 21 of the repeat coil is ing detailed description in connection with the connected .across line 3i which leads to a remote 50 accompanying drawing, the single figure of observing point where headset 32 and recorder which shows an impulse producing circuit utiliz- 33 are provided being connected as desired across ing an embodiment of the invention. line 3! under control of switches 37 and 38. The

Referring now to the drawing the arrangement impulses may be listened to by means of the illustrated may be utilized, to mention only one headset and the significant impulses (i. e. the 55 discharge impulses) may be readily distinguished from the charge impulses by the listener'due to their substantially greater amplitude. If the impulses are recorded on recorder 33 which may be of any suitable type, for example, a spark chronograph, the substantial difference in amplitude of the two types of impulses renders possible the recording thereof in a distinguishable manner. In fact by proper choice of circuit elements the amplitude of the charge impulses may be rendered so small that these impulses will not be recorded, only the significant discharge impulses being recorded.

While a certain specific embodiment of the invention has been selected for detailed description the invention is not limited in its application to the embodiment described. The embodiment described should be taken as illustrative of the invention rather than as restrictive thereof.

What is claimed is:

1. In an impulse producing circuit including a condenser and means for periodically charging and discharging said condenser, means for utilizing the charge and discharge impulses to produce sound, and means conductively associated with the charging and discharging paths of the impulse producing circuit for so modifying the characteristics of the charge impulses as compared to the discharge impulses that said charge impulses and said discharge impulses shall be readily distinguishable one from the other by the sounds which they produce.

2. In an impulse producing circuit including a condenser and means for periodically charging and discharging said condenser, means for rendering the charge impulses distinguishable from the discharge impulses, said last-mentioned means being conductively associated with the charging and discharging paths of said condenser and being effective to cause a substantial difierence in the impedance oiIered by said impulse producing circuit tothe charging currents as compared to the impedance ofiered to the discharge currents.

3. In an impulse producing circuit including a condenser and means for periodically charging and discharging said condenser, means for rendering the charge impulses distinguishable from the discharge impulses, said last-mentioned means comprising a rectifier associated with the charging and discharging paths of said condenser and effective to present a relatively high impedance to currents in one direction with regard to said condenser and a relatively low impedance to currents in the oppos'me direction with regard to said condenser.

4. In combination, an impulse produc ng circuit, including a condenser and means for periodically charging and discharging said condenser, a line, means for coupling the output of said condenser to said line, and means connected between said condenser and said coupling means conductively associated with the charging and discharging paths of said condenser and effective to provide a relatively high impedance to currents passing through said coupling means in one direction and a relatively low impedance to currents passing through said coupling means in the opposite direction.

5. In combination, an impulse producing circuit including a condenser and means for periodically charging and discharging said condenser, a line, a multi-winding inductive device for electrically coupling said impulse producing circuit and said line, and a rectifier in said impulse producing circuit, said rectifier being connected in series with one terminal of said condenser and one terminal of one winding of said coupling device and being effective to cause a substantial difierence in the amplitude of impulses passing through said one winding in one direction from the amplitudeof impulses passing through said one winding in the opposite direction, said winding being included in the charging and discharging paths of said condenser.

6. In an impulse producing circuit including a condenser and means for periodically charging and discharging said condenser, means for so modifying the characteristics of the charge impulses as compared to the discharge impulses that said charge impulses and said discharge impulses shall be readily distinguishable one from the other, said means being conductive both with re-,

spect to the charge impulses and with respect to said discharge impulses but to a substantially greater degree with respect to one type of said impulses than with respect to the other type.

7. In an impulse producing circuit including a condenser and means for periodically charging and discharging said condenser, means for causing a substantial difierence in the amplitude of thecharge impulses from the amplitude of the discharge impulses, said means being conductive with respect both to said charge impulses and said discharge impulses but offering a substantially greater impedance to one type of said impulses than to the other type.

8. In an impulsing circuit, a source of current in series relation with: an interrupter, a condenser, an imperfect rectifier and an indicating device; said source being poled to send reverse current through said rectifier and said indicating device into said condenser when said interrupter is in circuit closing position to charge said condenser, a discharge path for permitting said condenser to discharge through said rectifier in its low resistance direction into said indicating device when the interrupter opens the charging circuit, and means for operating said interrupter periodically to open and close said charging circuit.

RALPH L. MILLER. 

